Field of the Invention
The present invention relates to a soft start circuit and a power supply device equipped therewith.
Background Art
A power supply device such as a DCDC converter has generally been provided with a soft start circuit for preventing an inrush current at power-on.
The related art soft start circuit is accompanied by a problem that it needs a capacitor high in capacitance value to obtain a soft start voltage which rises in a few millisecond's time, and occupies a large area within an IC chip.
To cope with such a problem, there has been proposed in Patent Document 1, a method of adapting such a configuration that a switch is turned ON/OFF using a clock signal and a capacitor is intermittently charged with a constant current, thereby reducing the capacitor and suppressing a circuit scale.
[Patent Document 1] Japanese Patent No. 4853003